Ultra Precise Modular Reaction Wheel Operation for Optical and Radar Satellites

With the new space arena evolving towards serious science and defense missions, the availability of new space avionics with high-end performance is becoming a prerequisite for modern and future satellite missions. This puts requirements for very accurate speed and torque control of modern reaction wheels used to perform attitude control of modern spacecraft. Nearly vibration free operation (optical payloads) Extremely trum of frequencies Modularity Fast delivery Scalabilit

Multivisceral ‘en-bloc` resections of colorectal tumours - milestones in the surgical techniques

Purpose: Colorectal tumours (CRT) consisting mainly of colorectal cancer (CRC) are diagnosed sometimes at an advanced T4 stage, i. e. local involvement of neighbouring organ/organs and anatomical structure/ structures. Aggressive surgical approach preceded and/or followed by neo-adjuvant/adjuvant therapy is advocated because of proven benefit for the patient. The aim of this study was to carry out a literature survey, on the one hand, and to analyze the cases from the authors` institutional experience, on the other hand, in an attempt to submit for consideration the milestones of the multivisceral en-block resections in cases of locally advanced CRTs, i.e. to describe the specific surgical approaches depending on different tumour location and peritumoural involvement of adjacent structures and organs.Material and methods: A retrospective analysis of 154 cases of CRT was performed, all of them operated in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital of Sofia, from January 1, 2007 to March 31, 2013. All the patients were diagnosed in an advanced T4-stage and received multivisceral en-bloc resections. Three main groups of methods that had been used were analyzed: 1) preoperative diagnosis, giving a hint of multivisceral en-bloc resection; 2) intraoperative assessment - gross tumour appearance, frozen sections (?), final histological examinations, and 3) surgical methods.Results: Early morbidity and mortality rates were 22,6% and 5,8%, respectively, without any significant difference when compared with ‘simple` colon and rectum resections and with literature data available.Conclusion: Multivisceral en-bloc resection for CRCs has been performed in more than 10% of the cases. It benefits the long-term prognosis. Tumour location and number of resected organs are essential characteristics of these procedures and they are independently associated with the quantity of intraoperative blood loss, higher early morbidity rates and more frequent local recurrence

Locally advanced adenocarcinoma of the supramesocolic part of the colon . Feat ures of surgical treatment and challenges

Purpose: The objective of the present study was to analyze the early results from the surgical treatment of locally advanced carcinoma of the colon in its transverse section and the two flexures.Material and methods: The study covered 36 patients with locally advanced colonic carcinoma, 19 males and 17 females at a mean age of 65,6 years, treated in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital of Sofia during the period from January 2007 to March 2013. Any necessary diagnostic and surgical methods were applied.Results: Multivisceral resections were commonly performed in order to achieve a radical surgery in cases of locally advanced disease. Great surgeon`s experience in liver, biliary and pancreatic interventions is obligatorily required. In this paper we share our experience in the treatment of this disease for a period of 6 years.Conclusion: Our application of the multivisceral resections results in surgical radicality along with acceptable levels of perioperative morbidity and mortality rates when compared to other studies in in the foreign literature available

Early perioperative res ults in 53 cases of locally rec urrent colorectal cancer

Purpose: The objective of this study was to analyze retrospectively the early perioperative results in a cohort of 53 patients with localy reccurent colorectal cancer (CRC).Material and methods: The study covered 53 patients with CRC 21 males and 32 females at a mean age of 62 years treated in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital of Sofia, during the period from January 2007 to March 2013. Any necessary diagnostic and surgical methods were applied.Results: The locally recurrent CRC is a challenge for the surgeon because of the fact that in most cases it engages adjacent anatomical structures and organs, on the one hand, and it is accompanied by complications, on the other hand.Conclusion: Achievement of good late results in patients with recurrent CRC is due to radicality of the interventions. Most often, they should be multivisceral resections. The presence of intestinal obstruction of varying degree and of synchronous peritoneal and liver metastases commonly limit the possibilities for surgical interference with the disease. Particular attention should be paid to possible neoadjuvant treatment capable of reducing the stage of diasease and improving the perioperative outcomes. Therapeutic behaviour should be strictly individual and consider any possible options. The experience of the surgical team is extremely important, too

Clinico-pathological prognostic factors in hematogenously disseminated colorectal cancer

Background: Ekberg`s criteria for liver resections (LR) of colorectal cancer liver metastases (CRCLM) have been accepted as a `dogma` and the procedure - as a `gold standard` since 1986. There are many wellknown predictive factors for the early and long-term results in this field of surgery. However, some of them are still a matter of debate.Aim: Study on the possible prognostic value of some clinical-pathological factors for the early and late results after major LR (≥ 2 segments) of CRCLM.Material and methods: A total of 143 radical (R0) major LR (≥ 2 segments) of synchronous and metachronous CRCLM were performed between 01.01.20007 - 31.12.2014 in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital Sofia. The design of the study was `a single center` and `retrospective`. We analyzed the data with possible predictive value - demography, comorbidity, liver function, ASA group, neoadjuvant chemotherapy, type and characteristics of the surgical procedure, pathological data (T,N,G,H) and time of detection of metastases (synchronous or metachronous). The early postoperative morbidity and mortality rates were compared with these factors looking for correlation. The long-term follow-up period was ≥ 12 months for 86 patients (60.1%).Results: The early postoperative mortality rate was 2.8% (4 cases) for the whole series. The specific morbidity rates were significantly higher in patients above 65 years of age, with ≥ 3 comorbid conditions, multivisceral resections in cases of synchronous metastases and atypical (non-anatomical) LR. The majority of CRCLM cases were ≥ Т2, N (+) positive and G2-3. Unfavorable prognostic factors were the detection of metachronous lesions earlier than 12 months after a curative previous resection especially on the basis of adequate chemotherapy.Conclusions: The knowledge on prognostic factors in patients with CRCLM as well as on indications and contraindications helps the correct preoperative judgment on choosing the right and appropriate type and volume of surgical procedures

Comparative analyses between the early postoperative results after major liver resections of colorectal and noncolorectal cancer liver metastases

Background: Liver resections (LR) are an obligatory element in the multimodal treatment scheme of colorectal cancer liver metastases (CRCLM). Nowadays still there are debates about the benefit of any aggressive surgical approach in noncolorectal cancer liver metastases (NCRCLM) because many authors report desperately high rates of early specific post-resection complications (SPRC) followed by unsatisfactory long term results.Aim: Comparative analyses between the SPRC after major liver resections (MLR), i.e. ≥ 2 segments of CRCLM and NCRCLM for confirming or denying the hypothesis of higher risk in the group of NCRLM.Material and methods: A total of 331 MLR of benign and malignant tumors were performed between 01.01.2007 - 31.12.2014 in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital Sofia. Radical resections received 143 CRCLM patients and 58 NCRCLM patients, both synchronous and metachronous. The design of the study was `a single center` and `retrospective`. The perioperative data of these 201 patients were analyzed and finally 59 cases of CRCLM (Group 1) and 36 cases of NCRCLM (Group 2) were included in the study. All the metastases were metachronous and no significant differences in demography, comorbidity, liver function, ASA group, neoadjuvant chemotherapy and surgery specificity were detected between the two groups. Cases that were indicated for MLR were those under 65 years of age, with preserved liver function, without serious pulmonary and cardiac concomitant diseases, and estimated as ASA group ≤ III. Data about SPRC were collected and analyzed. Results: The entire early postoperative mortality rate was 3.2% (3 fatal outcomes) - 1/59 (1.7%) in group 1 and 2/36 (5.5%) in group 2. The cause of death was liver failure, sepsis and pulmonary embolism. The rate of SPRC was significantly higher in group 2, affecting 16/36 patients (44.4%) while only 18 out of all the 59 patients (30.5%) in group 1 suffered specific complications. However only 5.1% and 8.3% of the SPRC necessitated reoperations in group 1 and group 2 respectfully. The comparative analysis denied any prognostic value for the early SPRC played by the time of metastases detection, adjuvant chemotherapy, the duration of liver resection procedure and the necessity of blood transfusion. Conclusions: Both mortality and specific morbidity after MLR affected patients with ≥3 comorbid conditions which proved to be the only predictive factor for SPRC. SPRC were more frequent in group 2 (NCRCLM) but the great majority of them were solved by conservative measures, less often by interventional procedure and reoperations were indicated very rarely

Durability and wear resistance of laser-textured hardened stainless steel surfaces with hydrophobic properties

Hydrophobic surfaces are of high interest to industry. While surface functionalization has attracted significant interest, from both industry and research, the durability of engineered surfaces remains a challenge, as wear and scratches deteriorate their functional response. In this work, a cost-effective combination of surface engineering processes on stainless steel was investigated. Low-temperature plasma surface alloying was applied to increase surface hardness from 172 to 305 HV. Then, near-infrared nanosecond laser patterning was deployed to fabricate channel-like patterns that enabled superhydrophobicity. Abrasion tests were carried out to examine the durability of such engineered surfaces during daily use. In particular, the evolution of surface topographies, chemical composition, and water contact angle with increasing abrasion cycles were studied. Hydrophobicity deteriorated progressively on both hardened and raw stainless steel samples, suggesting that the major contributing factor to hydrophobicity was the surface chemical composition. At the same time, samples with increased surface hardness exhibited a slower deterioration of their topographies when compared with nontreated surfaces. A conclusion is made about the durability of laser-textured hardened stainless steel surfaces produced by applying the proposed combined surface engineering approach

Crohn's Disease Complicated by Ileosigmoid Fistula - Synchronous Resection or Primary Sigmoid Repair, One or Two-stage Procedure? A systematic review of the literature and prospective case series

Introduction: Although ileosigmoid fistulas (ISFs) in Crohn’s disease (CD) are rare they can be quite challenging, especially for the inexperienced surgeons. Furthermore, current guidelines offer no clear recommendation regarding the surgical strategy in such cases. A systematic review of the literature to determine the best surgical strategy and a prospective case series are presented herein.  Materials and methods: The systematic review was performed according to PRISMA guidelines. A single-center prospective data-base from January 1, 2014 to August 20, 2019 is presented. Age, duration of CD, and the rates of ISF, emergency, preoperative diagnosis, type of surgery, type of stoma, and complications were analyzed and a prospective case series. Results: Eleven of 69 papers with a total of 505 patients were included in the systematic analysis. The rate of ISF was 3–5% of all CD patients. The combined preoperative detection rate of all modalities was 71%. Primary repair was performed in 42% of the cases; the rate of stoma was 31.5% with a similar proportion in primary repair and sigmoid resection.In the presented series, 35 of 176 patients with CD were operated (51% in an emergency setting). There were 7 cases with ISFs (4% of all and 20% of the operated patients). Preoperative diagnosis was made at 57%. Primary repair was performed in 71%, and a two-stage intervention with a stoma – in 58% of patients. Conclusions: Primary repair should be attempted in all cases in which the sigmoid colon is disease-free or is not involved in the adja-cent abscess. The synchronous resections are not a mandatory indication for the stoma, but rather a tailored approach is recommended with an evaluation of the risk factors. Based on the available literature, no clear recommendation regarding the type of stoma can be made

Novel Styrylquinolinium Dye Thin Films Deposited by Pulsed Laser Deposition for Nonlinear Optical Applications

The nonlinear optical (NLO) properties of novel styrylquinolinium dye thin films for photonic applications have been studied by the Z-scan, second harmonic generation (SHG), and third harmonic generation (THG) techniques, providing both the second- and third-order nonlinear optical parameters. The styrylquinolinium dye (E)-1-ethyl-4-(2-(4-hydroxynaphthalen-1-yl)vinyl)quinolinium bromide was synthesized by the Knoevenagel condensation, and its structure and physicochemical properties were determined by H-1 NMR, C-13 NMR, FTIR, UV-vis spectroscopy, and elemental analysis. Functional thin films were deposited by pulsed laser deposition (PLD) using UV TEA N-2 laser onto glass substrates and KCl, NaCl monocrystals at room temperature and vacuum at 10(-3) mbar/0.1 Pa. Further characterization of the films and target from native material by FTIR spectroscopy revealed that there was no difference between the deposited films and the initial material. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements have been also performed in order to provide information about the morphology and topology of the thin films

Mutation increasing β-carotene concentrations does not adversely affect concentrations of essential mineral elements in pepper fruit

<div><p>Vitamin and mineral deficiencies are prevalent in human populations throughout the world. Vitamin A deficiency affects hundreds of millions of pre-school age children in low income countries. Fruits of pepper (<i>Capsicum annuum</i> L.) can be a major dietary source of precursors to Vitamin A biosynthesis, such as β-carotene. Recently, pepper breeding programs have introduced the orange-fruited (<i>of</i>) trait of the mutant variety Oranzheva kapiya, which is associated with high fruit β-carotene concentrations, to the mutant variety Albena. In this manuscript, concentrations of β-carotene and mineral elements (magnesium, phosphorus, sulphur, potassium, zinc, calcium, manganese, iron and copper) were compared in fruit from P31, a red-fruited genotype derived from the variety Albena, and M38, a genotype developed by transferring the orange-fruited mutation (<i>of</i>) into Albena. It was observed that fruit from M38 plants had greater β-carotene concentration at both commercial and botanical maturity (4.9 and 52.7 mg / kg fresh weight, respectively) than fruit from P31 plants (2.3 and 30.1 mg / kg fresh weight, respectively). The mutation producing high β-carotene concentrations in pepper fruits had no detrimental effect on the concentrations of mineral elements required for human nutrition.</p></div